Bt8960
Single-Chip 2B1Q Transceiver
The Bt8960 is a full-duplex 2B1Q transceiver based on Rockwell’s HDSL technol-
ogy. It supports Nx64 kbps transmission of more than 18,000 feet
over 26 AWG
copper telephone wire without repeaters. Small size and low power dissipation
make the Bt8960 ideal for line-powered voice pairgain systems capable of provid-
ing four or six clear 64 kbps channels.
The Bt8960 is a highly integrated device that includes all of the active circuitry
needed for a complete 2B1Q transceiver. In the receive portion of the Bt8960, a
variable gain amplifier optimizes the signal level according to the dynamic range
of the analog-to-digital converter. Once the signal is digitized, sophisticated adap-
tive echo cancellation, equalization, and detection DSP algorithms reproduce the
originally transmitted far-end signal.
In the transmitter, the transmit source and scrambler operation is programma-
ble via the microcomputer interface. A highly linear digital-to-analog converter
with programmable gain, sets the transmission power for optimal performance. A
pulse-shaping filter and a low distortion line driver generate the signal character-
istics needed to drive a large range of subscriber lines at low-bit error rates.
Startup and performance monitoring operations are controlled via the micro-
processor interface. C-language source code supporting these operations is sup-
plied under a no-fee license agreement from Rockwell. The Bt8960 includes a
glueless interface to both Intel and Motorola microprocessors.
Functional Block Diagram
Distinguishing Features
• Single-chip 2B1Q transceiver solution
• All 2B1Q transceiver functions inte-
grated into a single monolithic device
– Receiver gain control and A/D
converter
– DSP functions including echo
cancellation, equalization, timing
recovery, and symbol detection
– Programmable gain transmit DAC,
pulse-shaping filter and line driver
• Supports operation from 160 to 416
kbps
• Capable of transceiving over the ANSI
T1.601 and ETSI ETR 080 ISDN
test loops
• Flexible Monitoring and Control
– Glueless interface to Intel 8051 and
Motorola 68302 processors
– Access to embedded filters, perfor-
mance meters and timers
• Backwards compatible with Bt8952
software API commands
• JTAG/IEEE Std 1149.1-1990
compliant
• Single +5 V power supply
operation
• 600 mW power consumption at 288
kbps (typical)
• 100-pin PQFP package
• –40˚C to +85˚C operation
Applications
• Voice/data pairgain systems
• Internet connectivity
• ISDN basic-rate interface
concentrators
• ISDN H0 transport
• Extended range fractional T1/E1
• Cellular/microcellular base stations
• Personal Communications Systems
(PCS) radio ports and cell switches
Analog
Receive
MPU
Bus
Analog
Transmit
Variable
Gain
Amplifier
Microcomputer
Interface
Line
Driver
Pulse-
Shaping
Filter
Program-
mable
Gain
DAC
Analog-
to-Digital
Converter
Digital
Signal
Processor
Framer/
Channel
Unit
Interface
Recovered
Data and
Clock
Transmit
Data
